Flow cytometry and cell sorting are inetegral and non-dispensible components of modern biomedical research. These techniques allow for the rapid identification of individual cells within a mixed population based on such properties as cell surface antigen expression, cell cycle status, cell signaling, or fluorescencetagged transgenes. Furthermore, once cell populations are identified they can be isolated into discreet populuations via cell sorting. The University of Colorado Cancer Center Flow Cytometry Core is a state-ofthe- art facility that provides two machines capable of high speed cell sorting based on 7-color or 9-color parameters, respectively. Additionally the core provides three flow analysis machines capable of 4, 5, and 9- color analysis, respectively.The Flow Core also provides the Luminex system for multiplexed bead array analysis. Additionally Flow Core personnel provide a consulting service for analysis and cell sorting strategies. The Flow Core will be used extensively for investigators involved in skin disease: we will be capable of identifying and isolating various skin cell subpopulations, such as keratinocytes and keratinocyte stem cell populations, as well as isolating normal and tumor skin stem cells from tissues or cell cultures for further in vitro and in vivo analysis. Additionally investigators will be able to identify, isolate, and further assess phenotype-specific T cell or other immune cell populations associated with various skin pathologies. ore center support for the Flow Core will insure that investigators of the Skin Disease Research Core Center (SDRC) will have full access to all services provided by the Flow Cytometry and Cell Sorting Core at a discounted rate.